Chapter 8 Managing Databases in the Cloud
Which of the following AWS cloud services enable you to store data? (Choose three) A. Amazon ElastiCache B. Amazon DynamoDB C. Amazon RDS D. Amazon Simple Queue Service (Amazon SQS)
A, B, C. Amazon ElastiCache, Amazon DynamoDB, and Amazon RDS are all AWS database storage services.
Which of the following can help an RDS MySQL database instance handle thousands of new application users? (Choose three) A. Upgrade storage from magnetic volumes to General Purpose SSD volumes. B. Use Read Replicas to distribute the read requests. C. Vertically scale the DB instance by switching the instance to a larger instance class. D. Move the database users to Amazon ElastiCache.
A, B, C. General Purpose SSD volumes, Read Replicas, and larger instance classes are all good ways to handle an increasing RDS database workload.
Which of the following actions will help you protect your databases in the AWS cloud? (Choose three) A. Grant permissions on database objects to the database users. B. Limit network access by configuring security groups and network access control lists (ACLs). C. Configure AWS Identity and Access Management (IAM) permissions for the administrators. D. Remove all database user accounts from the databases.
A, B, C. You can enhance database security by controlling permissions on the database objects, configuring security groups and ACLs, and by configuring IAM permissions for the administrators.
Which of the following AWS services come with an out-of-the-box automatic backup as a service (BaaS) and backup rotation options? (Choose two) A. Amazon RDS B. Amazon Redshift C. Amazon DynamoDB D. AWS CloudFormation
A, B. Amazon RDS and Amazon Redshift offer the ability to back up the database automatically (through automatic snapshots), and an option to store the backups in Amazon S3.
Which of the following are true regarding Amazon RDS database backups? (Choose all that apply) A. All automated backups are deleted when you delete a DB instance. B. All manual snapshots are deleted when you delete a DB instance. C. You can change the engine type when performing an Amazon RDS DB instance restore operation. D. Manual snapshots persist until you delete them manually.
A, C, D. When you delete a DB instance, all automated backups are deleted, but manual snapshots that you've taken will persist until you manually delete them. You can change the engine when restoring an RDS DB instance.
Which of the following are true regarding an Amazon RDS Read Replica? (Choose three) A. It's possible to place Read Replicas in a different AWS region from that of the primary DB instance to be closer to the users and improve its performance. B. Read Replicas help you vertically scale a database. C. Read Replicas help you horizontally scale a database. D. Read Replicas can enhance the availability of a database.
A, C, D. You can place the Read Replicas of a DB instance in a different AWS region from that of the primary DB instance to be closer to your users and to enhance performance. Read Replicas help you horizontally scale a database by adding more replicas to enhance read performance. Read Replicas can enhance database availability by enabling users to read from them.
Which of the following help you to you improve your database storage performance by reducing the wait time for the database's storage volume, without affecting the persistence of the data? (Choose two) A. Use Amazon EBS-Optimized EC2 instance type. B. Switch to an Amazon S3-based storage for the database. C. Use an EC2 instance with an Instance Store volume. D. Use a Provisioned IOPS Amazon EBS volume.
A, D. You can improve performance by using Amazon EBS-Optimized instances and by choosing Provisioned IOPS storage.
Which of the following AWS databases offers a non-relational database? A. Amazon DynamoDB B. Amazon Redshift C. Amazon RDS D. Amazon S3
A. Amazon DynamoDB is a non-relational (NoSQL) database service.
When you configure Amazon RDS Multi-AZ deployment, which of the following is true? A. Amazon RDS synchronously replicates data from the primary DB instance to the standby DB instance in a different AZ. B. Amazon RDS asynchronously replicates data from the primary DB instance to the standby DB instance in a different AZ. C. Amazon RDS synchronously replicates data from the primary DB instance to the standby DB instance in a different AWS region. D. Amazon RDS asynchronously replicates data from the primary DB instance to the standby DB instance in a different AWS region.
A. RDS automatically creates the standby DB instance in a different AZ from that of the primary DB instance. RDS synchronously replicates the primary DB instance to the standby replica to provide data redundancy, to minimize latency hits during a system backup, and to eliminate I/O freezes.
When you run a DB instance in a Multi-AZ primary/standby configuration in two different AZs, can you use the standby DB instance for distributing the read requests made to the database? A. No B. Yes C. Only for specific database engines supported by RDS D. Yes, provided you make the standby a read-only database
A. When you run a high availability database configuration with primary and standby database instances, you are protected against a DB instance or AZ issue that makes the primary DB instance unavailable. This is not a solution for scaling your database, since the standby DB instance can't serve read requests. If you want to distribute the read traffic being served by the database, you can do so by creating Read Replicas.
Which of the following can you encrypt by enabling the encryption option for an Amazon RDS DB instance? (Choose three) A. The file system that supports the RDS instance B. Automated backups of the DB instance C. Read Replicas of the DB instance D. Snapshots
B, C, D. By enabling the encryption option for an RDS DB instance, you can encrypt automated database backups, Read Replicas of the instance, and the database instance snapshots.
Which of the following are true about DB security groups and VPC security groups? (Choose two) A. A DB security group controls access to DB instances in a VPC. B. A DB security group controls access to DB instances outside a VPC. C. A VPC security group controls access to DB instances in a VPC. D. A VPC security group controls access to DB instances outside a VPC.
B, C. A DB security group controls access to EC2-Classic DB instances that are not in a VPC. A VPC security group controls access to DB instances and EC2 instances inside a VPC.
What are the implications of the eventually consistent reads feature in DynamoDB? (Choose two) A. When you read data from a table, it can never include stale data. B. When you read data from a table, the response may include some stale data. C. The database will always return the most up-to-date data. D. If you repeat your read request after the initial request, the database response should return the latest data.
B, D. The eventually consistent reads feature means that when you read data, the response from the database may include stale data. However, if you repeat your read request after some time, the response includes the latest version of the data.
Which of the following database storage types would be best for an application that gets occasional bursts of activity throughout the day? A. Magnetic storage B. General Purpose SSD (gp2) storage C. Provisioned IOPS (SSD) D. S3 storage
B. General Purpose SSD storage is best for databases that handle occasional bursts of activity.
Which of the following metrics helps you know when to re-create a Read Replica when the Read Replica becomes out of sync due to replication errors? A. ReadReplicaLag B. ReplicaLag C. ReadTimeLag D. ReadThreshold
B. The ReplicaLag metric reveals the time a Read Replica instance lags behind the source DB instance.
When you deploy databases in a Multi-AZ setup, a planned or unplanned outage of the primary DB instance results in a switch to the secondary DB instance. Which DNS record does the automatic failover update to point to the standby DB instance? A. SOA B. CNAME C. MX D. The A Record
B. When automatic failover occurs, your application can remain unaware of what's happening behind the scenes. The CNAME (canonical name) record for your DB instance is modified so it points to the newly promoted standby (which becomes the primary DB instance now).
Can you configure an RDS standby DB instance and a primary DB instance to run in the same AZ? A. Yes, always B. No, never C. Yes, but only if you configure this when you create a DB instance—not by modifying the DB instance later D. Yes, but only for some DB engine types
B. You can never configure both a primary and standby DB instance to run in the same AZ. RDS automatically provisions a standby DB instance in an AZ that's different from the region of the primary DB instance.
What is the range of the backup retention period for an RDS DB instance? A. 1-7 days B. 1-28 days C. 1-35 days D. 1-365 days
C. Amazon RDS saves all automated backups of a DB instance for the backup retention period that you configure. You can recover the DB instance to any point within the backup retention period. You can specify a backup retention period of 1-35 days.
Which of the following AWS services or databases will help a high-volume web application to scale up to handle a large number (hundreds of thousands) of concurrent users? A. Amazon Aurora B. Amazon Redshift C. Amazon DynamoDB D. Amazon ElastiCache
C. DynamoDB is a NoSQL database that can easily scale to hundreds of thousands of concurrent requests.
If you accidentally delete a large amount of critical business data, which of the following will enable you to restore the deleted data very quickly? A. A Multi-AZ deployment of the database B. RDS Read Replicas C. RDS snapshots D. RDS Auto Restore feature
C. RDS snapshots enable you to recover DB instances. If you're running a single AZ DB instance, recovery results in a slight suspension of I/O (a few seconds to a few minutes). If you're running a Multi-AZ DB instance, there won't be an I/O suspension, because RDS takes the snapshot on the standby DB instance.
What happens in a DynamoDB database when an application performs more reads and writes than the configured provisioned capacity? A. The requests that exceed the provisioned capacity are performed but will return a 400 HTTP error code. B. The requests that exceed the provisioned capacity will fail with a 500 HTTP error code. C. The requests that exceed the provisioned capacity will be throttled, with an HTTP 400 error code. D. The requests that exceed the provisioned capacity will be throttled, with an HTTP 500 error code.
C. When the read and write requests of an application exceed the provisioned throughput for a DynamoDB table, the database might throttle new requests. The requests will fail with a HTTP 400 code message of "Bad Request." You'll also receive an exception called the ProvisionedThroughputExceededException.
How does Amazon ElastiCache enhance application performance? A. It creates multiple DB instances so that they can split the work among themselves. B. It offers a single managed service that can run both relational and NoSQL databases. C. It catches rarely accessed data to reduce latency. D. It caches frequently accessed data.
D. Amazon ElastiCache caches frequently accessed requests. By offloading the read traffic from the databases, it reduces latencies induced by a read-heavy workload.
Can you force the failover of a MySQL DB instance Multi-AZ deployment? A. Only between some AZs B. Never C. Yes, if you run the databases in your Amazon VPC D. Yes
D. By performing a reboot with failover, you can always force a failover between two AZs. When you force the failover manually, Amazon RDS makes the current standby instance the primary DB instance. It also updates the DNS record (the CNAME record) for the instance so it now points to the new primary DB instance. You must therefore reestablish all existing connections to the DB instance. You perform a reboot with failover when you want to test the impact of a DB instance failure or to restore database operations to the original AZ following a failover.
Which of the following methods is the quickest way to install the Microsoft SQL Server Enterprise Edition DB instance on Amazon RDS? A. Install the SQL Server command line tools on your laptop and use the AWS CLI to provision the new RDS instance. B. Amazon RDS doesn't support the SQL Server Enterprise Edition. C. Use the License Included Option in the RDS console to install the SQL Server Enterprise Edition. D. Launch an RDS DB instance and select the Enterprise Edition under the bring your own license (BYOL) model.
D. Only the BYOL model offers the Microsoft SQL Server Enterprise Edition in RDS.
When you receive an alert that your primary RDS DB instance has gone down in a Multi-AZ RDS DB instance setup, what must you do to ensure a fast failover? A. Update the Domain Name System (DNS) to point to the secondary instance's new IP address. B. Log into the servers and update the connection strings of the applications so they communicate with the secondary DB instance. C. Create a new secondary DB instance from the latest snapshot of the primary DB instance. D. Do nothing; AWS will automatically update the database endpoint, so that it now points to the secondary DB instance. The connection string always points to the database endpoint.
D. You don't need to do anything, since AWS will automatically update the DB endpoint to point to the secondary instance, which now becomes the primary instance.
